About Chronic Myelogenous (Myeloid) Leukemia (CML)
Chronic Myelogenous Leukemia (CML) is a type of blood and bone marrow disease characterized by the overproduction of white blood cells. CML is also called chronic myeloid leukemia or chronic granulocytic leukemia.
It typically occurs in middle-aged or older individuals but rarely affects children. CML is caused by a gene mutation called the Philadelphia chromosome, which results in the abnormal production of white blood cells. The disease progresses slowly and has different phases, including chronic phase, accelerated phase, and blastic phase. In the chronic phase, the involvement is usually limited to the blood, bone marrow, and spleen. As the disease progresses to the accelerated and blastic phases, lymph nodes and tissues may also be affected.
CML is diagnosed through blood and bone marrow tests. Treatment options and prognosis depend on various factors. It's important to consult with a healthcare professional for accurate diagnosis and personalized treatment recommendations.
CML is a type of cancer that affects the blood and bone marrow. The exact cause of CML is still unknown, but it is believed to be caused by a mutation (change) in a person's genes. This change leads to the overproduction of immature white blood cells in the bone marrow.
Non-modifiable risk factors for CML (factors a person can’t change or control) include:
- Age: CML is more common in adults, with the average age of diagnosis being around 60 years old. CML is not common in children and teens
- Sex: Males assigned at birth have a greater chance of developing CML than females assigned at birth.
- Previous exposure to high-dose ionizing radiation: Long-term exposure to high levels of radiation, such as from radiation therapy, may increase the risk of CML.
Currently, there are no definitive modifiable risk factors for CML (factors a person potentially can change or control). Some studies suggest that exposure to certain chemicals or substances in the workplace or environment may be associated with an increased risk of CML. However, more research is needed to establish a clear link.
It's important to note that having these risk factors does not guarantee that someone will develop CML. Conversely, not having these risk factors does not mean that someone will not develop CML. If you have concerns about your risk or symptoms, it's best to consult with a healthcare professional for an accurate evaluation.
Some people who have CML do not have symptoms. Common symptoms of CML may include:
- Fatigue
- Shortness of breath
- Easy bruising or bleeding
- Frequent infections
- Fever for no known reason
- Night sweats
- Decreased appetite
- Unintentional weight loss
- Pain or discomfort in the upper abdomen, beneath the ribs
As CML progresses, additional symptoms may include:
- Severe anemia, leading to symptoms such as headaches, irritability, loss of appetite, numbness and tingling in hands and feet, weakness, severe fatigue, paleness, dizziness, and light-headedness.
- More severe bleeding and bruising
- Flat red spots on the skin (petechiae)
- Rashes
- Swollen abdomen
- Other cancers
- Bone or joint pain
- Swollen lymph nodes
It's important to note that these symptoms can vary from person to person. If you experience any concerning symptoms or have any questions, it's best to consult with your healthcare professional for an accurate diagnosis and appropriate management.
To diagnose CML, the following examinations, tests, and procedures may be performed:
- Health history: The healthcare professional will gather information about symptoms, past illnesses, current medical conditions and medications, and family medical history.
- Physical exam: The healthcare professional examines the body to check for signs of disease, such as enlarged lymph nodes or spleen, or anything unusual.
- Diagnostic tests and procedures for CML may include:
- Complete blood count (CBC) with differential: A blood sample is drawn and checked to determine the number and type of white blood cells, red blood cells, platelets, and hemoglobin levels.
- Blood chemistry studies: A blood sample is analyzed to measure the amounts of certain substances released into the blood by organs and tissues in the body.
- Peripheral blood smear: A pathologist will analyze a blood sample using a microscope to look for cancerous blood cells.
- Flow cytometry: This test helps determine if there are CML cells in the blood.
- Bone marrow biopsy: A sample of bone marrow tissue and fluid is obtained and sent to a pathologist look for signs of leukemia.
To determine the severity of CML and obtain information to help with treatment decisions, additional examinations, tests, and procedures may be recommended to determine if CML has spread to other areas of the body:
- Genetic tests: Samples of blood, saliva, or other tissues are used to identify changes in genes, chromosomes, or proteins that may be associated with CML. For CML, they will specifically look for the Philadelphia chromosome or the BCR-ABL gene. They can confirm or rule out a suspected genetic disease and help determine the risk of developing or passing on a genetic disease.
- Imaging studies: X-rays, MRIs, or CT scans may be performed to evaluate if CML has spread to internal organs.
- Lymph node biopsy: A sample or an entire enlarged lymph node may be removed to determine if leukemia has spread.
- Lumbar puncture: If there is a suspicion that CML has spread to the central nervous system, a small fluid sample may be taken from the lower spine for analysis.
Based upon the results, CML will be classified into a phase. The phases are determined by how much of the bone marrow is comprise of CML cells (immature white blood cells, or blasts):
- Chronic phase: Early, slower growing phase. Blasts comprise about 10% of the cells in the blood and bone marrow. This phase generally has the best response to treatment.
- Accelerate phase: This is a transitional phase where the CML starts to become more aggressive. Blasts comprise between 10% to 20% of the blood and bone marrow.
- Blast phase: This is a severe, very aggressive phase. Blasts comprise 20% or more of cells in the bone marrow and blood. A blast crisis is when the blast phase is accompanied by fatigue, fever and an enlarged spleen. A blast crisis may be life-threatening.
It is important to follow up with your healthcare provider if your symptoms worsen or change after the initial physical exam. They will guide you through the necessary diagnostic steps based on your individual situation.
The goals of treatment for CML may differ based upon the individual situation. Generally, goals may be to:
- Achieve remission: The main goal is to achieve a complete cytogenetic response, which means no evidence of the abnormal chromosome associated with CML. This is typically done through targeted therapy with tyrosine kinase inhibitors (TKIs) that block the activity of the abnormal protein driving the growth of CML cells.
- Prolong survival: Treatment aims to prolong the chronic phase of CML, during which patients can lead a normal life. TKIs are the mainstay of treatment. They inhibit signaling pathways that promote cell proliferation and induce apoptosis in CML cells without affecting normal cells.
- Improve quality of life: By controlling the disease and minimizing symptoms, treatment allows patients to maintain their daily activities and overall well-being.
Recommended treatments for CML include:
- Targeted therapy with TKIs: These medications specifically target and block the abnormal protein responsible for CML cell growth. TKIs may put CML into remission (no CML symptoms and no signs of CML in tests). TKIs may be life-long therapy for some people with CML.
- Chemotherapy: In some cases, chemotherapy may be used to help control CML. Chemotherapy may be used alone or given in combination with a TKI.
- Immunotherapy: These treatments boost the body’s immune system to fight the cancer. They may help slow tumor growth. An example of an immunotherapy is interferon.
- High-dose chemotherapy with donor stem cell transplant: This procedure involves giving high doses of chemotherapy to kill all blood-forming cells in a person’s bone marrow, then infusing healthy stem cells from a donor.
- Splenectomy: Surgical removal of the spleen may be considered in certain situations.
- Clinical trials: Participation in clinical trials can provide access to new treatments or therapies being investigated for CML.
It's important to note that treatment decisions should be made in consultation with a healthcare professional who can consider individual factors and tailor the treatment plan accordingly.
Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Side effects can occur. Check with your health care professional or read the information provided with your medication for additional side effect information.